Help with Credit Card Validation

[kismetgerald]

Thanks Brandon,

Thanks for your response. While waiting, I tried the following code and it seems to work very well:

Code:

Dim checksum As Integer = 0
        Dim doubleflag As Boolean = (value.Length Mod 2 = 0)

        Dim digit As Char
        Dim digitvalue As Integer
        For Each digit In value
            digitvalue = Integer.Parse(digit)
            If doubleflag Then
                digitvalue *= 2
                If digitvalue > 9 Then
                    digitvalue -= 9
                End If
            End If
            checksum += digitvalue
            doubleflag = Not doubleflag
        Next
        Return (checksum Mod 10 = 0)
    End Function

I will give try adding the Return line as suggested, and see how well this works.